Method and apparatus for crimping yarn



Feb. 4, 1969 D. A. E. MATTINGLY 3,425,106

METHOD AND APPARATUS FOR CRIMPING YARN Filed Jan. 24., 1966 Sheet of 5 v FIG; 7.

Feb. 4, 1969 D. A. E. MATTINGLY 3,425,106

METHOD AND APPARATUS FOR CRI-MPING YARN Filed Jan. 24. 1966 shes; 2 of s Feb, 4, 1969 D. E. MATTINGLY METHOD AND APPARATUS FOR CRIMPING YARN Filed Jan. 24. 19 6 3 FIG. 4.

United States Patent 5,755/65 US. Cl. 28-1 4 Claims Int. Cl. D02g 1/00; D023 1/22; D01d 5/22 ABSTRACT OF THE DISCLOSURE Yarn is crimped by first cold drawing the yarn between two spaced rollers and then immediately thereafter subjecting the yarn to linear compression in a closely adjacent, closed chamber. The heat generated in the yarn by the drawing operation is used to predispose the yarn for proper crimping thereby avoiding the need for supplying additional heat to the crimping chamber.

This invention relates to a method and apparatus for crimping yarn and particularly to a method and apparatus for drawing and crimping continuous multifilament thermoplastic yarn or yarn having a thermoplastic component.

The production of spun yarn is usually followed by a drawing process in which the yarn is stretched to cause a. reorientation of the molecular structure of the yarn in order to increase its tenacity. The amount of drawing, which may be by an amount several times the original length of the yarn, is varied according to the desired characteristics and denier of the drawn yarn. This drawing may be carried out in one or more steps, the yarn being drawn in stages until the desired yarn is obtained.

When the yarn is to be bunched or crimped by stulferbox crimping in which the yarn is compressed along its longitudinal axis, it is highly desirable for the yarn to be softened by heating the yarn prior to its entry into the stuffer-box crimping chamber so that a high degree of crimp can be imparted to the yarn.

According to one aspect of the present invention there is provided a method of crimping undrawn or partially drawn yarn comprising subjecting the yarn to a drawing operation between a first and second yarn engaging means whereby the yarn becomes at least partially softened, passing the softened yarn from the second yarn engaging means through a short distance into engagement with yarn feedingmeans and then crimping the softened yarn by subjecting it to linear compression.

Thus it will be seen that by means of the invention, the internal energy of the yarn released by the drawing operation which causes a temperature rise in the yarn and a consequent softening of the yarn is employed to assist in the crimping of the yarn. In this way a heating step can be eliminated with consequent economics in running costs.

The short distance is preferably less than 20 centimetres. The yarn is advantageously formed into a plug of crimped yarn and the plug of crimped yarn heated to set the crimp in the yarn.

According to another aspect of the present invention there is provided a method of texturising continuous filament yarn comprising the steps of cold drawing the yarn between a first and a second draw roller, the yarn thereby being softened, passing the softened yarn to a pair of nip rollers of a stutter-box crimper which feed the softened yarn into a crimping chamber at the same speed as the speed at which the softened yarn leaves the second draw roller, and crimping the softened yarn in the crimping chamber. The crimped yarn can be positively removed from the crimping chamber and then heated whilst being conveyed through a setting zone. The yarn can pass around a snubbing pin between said first and said second draw rollers the snubbing pin acting as a termination point for the drawing.

The yarn is advantageously guided substantially the whole distance between the second draw roller and the feed rollers of the stutter-box crimper to prevent filamentation of the yarn.

The yarn can pass around a separating roller adjacent each of said draw rollers whereby successive passes of the yarn around the draw rollers are axially spaced apart in a known manner.

According to a further aspect of the present invention there is provided apparatus for crimping undrawn or partially drawn yarn comprising a first draw roller and a second draw roller, said second draw roller being adapted to rotate at a peripheral speed greater than that of the first draw roller and said second draw roller being disposed adjacent a pair of nip rollers forming feed means to a stuffer-box crimping chamber. A snubbing pin can be included between the first draw roller and the second draw roller.

The apparatus can include a setting chamber having heating means and conveying means for removing the crimped yarn from the crimping chamber and conveying the crimped yarn through said setting chamber.

The apparatus may include for example a stuffer-box crimping machine such as is described in United States Patent No. 3,212,157 and copending United States patent application Ser. No. 470,954, now US. Patent No. 3,302,264, or in United States Patent No. 3,174,206.

The diameters of said first and second draw rollers can be at least twice the diameter of said nip rollers. A separating roller can be associated with each of said draw rollers, the axes of rotation of each of the separating rollers being inclined to the axis of rotation of the draw roller with which it is associated in a known manner.

The first and second draw rollers are advantageously disposed with their axes of rotation spaced apart by a distance less than twice the sum of their diameters and preferably less than the sum of their diameters. The first and second draw rollers and the nip rollers are advantageously disposed so that the length of the yarn path between said first and second draw rollers is greater than the length of the yarn path between the second draw roller and the nip rollers.

The apparatus can include guide means extending from the nip of said rollers to the point at which the yarn leaves the second draw roller to prevent ballooning and filamentation of the yarn particularly as it enters the nip of the nip rollers. The guide means can comprise a straight tube bell mouthed at each end to provide smooth surfaces over which the yarn can pass without snagging.

In some cases it may be desirable to provide means for maintaining the yarn in its heated and softened condition between the second draw roller and the nip rollers. Such means may be comprised simply by said guide means serving as insulation for the yarn. Alternatively the yarn may be maintained in its heated and softened condition by means of a heater over or through which the yarn is arranged to be passed.

Where the apparatus includes guide means in the form of a straight tube between the second draw roller and the nip rollers, the tube may be heated, for example by means of electrical heating wires disposed adjacent the outer surface of the tube, to provide the means for maintaining the yarn in its heated and softened condition.

It is to be understood that although the means for maintaining the yarn in a softened condition may comprise a heater, this heater will be very much smaller in power consumption and output than a heater required to heat soften yarn in crimping apparatus not employing the present invention, so that the technical and economic advantages of the invention are still obtained when a heater is employed to maintain the yarn in its softened condition.

The invention will now be described with reference to the accompanying diagrammatic drawings in which:

FIGURE 1 is a perspective view of part of one embodiment of apparatus according to the present invention;

FIGURE 2 is a view in the direction of arrow II in FIGURE 1;

FIGURE 3 is a perspective view of another embodiment of apparatus according to the present invention;

FIGURE 4 is an enlarged view of part of the embodiment of FIGURE 3.

Referring to FIGURE 1 a first driven draw roller 1 and a second driven draw roller 2 are rotatably mounted on a base plate 3. Associated with each of the driven rollers are separating rollers 4 and 5 mounted on the base plate so that they are freely rotatable about axes inclined to the axes of rotation of the draw rollers as shown in FIG- URE 2. Secured to the base plate between the two driven rollers 1 and 2 on a line joining their circumferences is a ceramic snubbing pin 6. Also secured to the base plate is a yarn guide 7.

The base plate 3 is secured to the framework (not shown) of a stuifer-box crimping machine such as is described in the above mentioned United States Patent No. 3,212,157 and copending United States patent application Ser. No. 470,954, now US. Patent No. 3,302,264, and represented in the drawing by a pair of nip rollers 8 and 9 for feeding the yarn into the crimping chamber, and a yarn guide 10.

The stulfer-box crimper, including the nip rollers 8 and 9, and the draw rollers 4 and 5 are driven through suitable transmission means so that the nip rollers and the roller 2 have the same peripheral speed, which peripheral speed is greater than the peripheral speed of roller 1.

In operation yarn 11 is passed through the yarn guide 7 to the first draw roller 1 and then about the separating roller 4 and back around roller 1. The yarn passes a number of times around the rollers 1 and 4, the separating roller 4, because it rotates about an axis at an angle to the axis of roller 1, distributing the yarn across the face of the roller 1. The yarn is then passed around the snubbing pin 6 and around the draw roller 2 and separating roller 5, the separating roller 5 distributing the yarn across the face of the roller 2. The yarn passes a number of times around the rollers 2 and 5. Draw rollers 1 and 2 grip the yarn and are driven so that the roller 2 has a greater peripheral speed than that of roller 1 so that the yarn is stretched or drawn between the two rollers. The snubbing pin acts as a termination point for thedrawing and rollers 4 and 5 are rotated by the yarn passing in contact therewith. The operation of drawing the yarn develops a quantity of heat in the yarn and the yarn is thereby softened.

The softened yarn is then passed around guide to the nip of the rollers 8 and 9 which are rotated at the same peripheral speed as the second draw roller 2, the rollers 8 and 9 feeding the yarn into the crimping chamber of a stuffer-box crimper.

By arranging for the distance between the draw roller 2 and the nip rollers 8 and 9 to be short, the heat developed in the drawing of the yarn is used to preheat and condition the yarn prior to its entry into the crimping chamber.

FIGURES 3 and 4 show another embodiment of the present invention in which yarn 12 is drawn from a supply bobbin 13 through a tensioning device 14. The yarn then passes a number of times around an idler roller 15 and a driven roller 16, roller 16 being secured to shaft 41 and then to a first separating roller 17 adjacent a first draw roller 18. The yarn passes a number of times around the rollers 17 and 18 before passing from roller 18 to a second draw roller 19, in this embodiment without passing around an intermediate snubbing pin. A second separating roller 20 is adjacent the second draw roller 19 and the yarn passes around the rollers 19 and 20 before passing to the nip of a pair of nip rollers 21 and 22. The axes of rotation of the separating rollers 17 and 20 are inclined to the axis of rotation of the draw rollers 18, 19 respectively, as is described hereinabove with reference to the embodiment of FIGURES 1 and 2.

The yarn passes from draw roller 19 to the nip rollers through tubular guide means 23 having bell mouthed ends to provide smooth entry and exit faces for the yarn.

The tubular guide means 23 may be provided, as is shown in FIGURE 4, with a longitudinal slot 42 to assist in threading up the apparatus. The slot 42 will of course be so disposed and arranged as not to snag the yarn as it passes through the tube 23.

Rollers 21, 22 are secured to shafts 24 and 25 respectively which are driven at a speed such that the peripheral speed of the nip rollers is the same as the speed of the draw roller 19.

The yarn is fed by the roller 21, 22 into a crimping chamber within the member 26 from which it is removed transversely as a plug of crimped yarn by a toothed wheel 27 secured to and driven by shaft 28, the plug of yarn clinging to the periphery of the wheel 27 and being conveyed through an arcuate groove formed within the member 26. Electric heating means 29 together with suitable control means 30 is provided for heating the arcuate groove in the member 26.

Crimped and set yarn is withdrawn from the leading end of the plug and passes through a guide 31, tensioning device 32 and further guides 33 and 34 before being formed into a package 35 on bobbin 36. The bobbin or package is rotated by a driven roller 37 contacting the periphery of the bobbin or package, roller 37 being secured to a driven shaft 38. The yarn is laid on the package in well known manner by a reciprocating guide adjacent the nip of the package and the drive roller.

As described more fully in the above mentioned United States Patent No. 3,174,206 light sensitive means 39 and 40 co-operate with sources of light disposed so that yarn within the arcuate groove can cut off the light source from reaching the light sensitive means opposite it. The outputs from each of the light sensitive means are arranged to operate means causing the rate of rotation of the drive roller 37 to vary so as to maintain the head of the plug of crimped yarn between the two light sensitive means 39, 40.

In operation the roller 16 is driven by shaft 41 so that its peripheral speed is the same as or greater than the peripheral speed of the first draw roller 18. As the yarn is gripped by the first draw roller 18 and the yarn is tensioned between the tensioning device 14 and the draw roller 18, roller 16 grips the yarn and assists in feeding the yarn through the apparatus.

The yarn is also gripped by the second draw roller 19 which has a greater peripheral speed than the first roller 18, the yarn being drawn several times its original length between the two draw rollers. Softened yarn leaving the second roller 19 passes through the tubular guide 23 to the nip rollers 21, 22. The tubular guide 23 serves to minimise cooling of the yarn by ambient air as it passes from roller 19 to the nip rollers and to prevent filamentation or ballooning of the yarn, the yarn having no twist in it to maintain the filaments together. To assist in maintaining the yarn in its softened condition and to minimise cooling, the tube 23 may be heated, by means of electrical heating wires (not shown) for example.

The nip rollers feed the yarn into the crimping chamber where the yarn is crimped by linear compression, the crimped yarn being formed into a plug of crimped yarn. The plug of yarn is removed from the crimping chamher by toothed wheel 27 at a rate substantially less than the rate at which the yarn is fed into the chamber. The yarn passes through the arcuate groove in the member 26 heat being applied to the yarn by the electric means 29 in order to set the crimp into the yarn.

Crimped and set yarn is Withdrawn from the leading end of the plug by the rotating bobbin 36 or' package 35 driven by roller 37, the tension in the yarn being formed into the package being controlled by the tensioning device 32.

In one example of apparatus constructed as shown in FIGURES 3 and 4 the draw rollers 18 and 19 were both centimetres diameter and their axes of rotation were 15.3 centimetres apart. The nip rollers 21, 22 were both 4.3 centimetres diameter and were spaced from the second draw roller 19 so that the yarn path from the roller 19 to the nip rollers 21, 22 was 12 centimetres.

I claim:

1. A method of texturizing undrawn or partially drawn yarn comprising the steps of cold drawing the yarn between a first and second draw roller, the yarn thereby being softened; guiding the softened yarn through a short distance to feed rollers of an unheated stutferbox crimper and during the passage of said yarn from said second draw roller to said feed rollers subjecting said yarn to heat to maintain said yarn in said softened condition and then crimping the softened yarn by subjecting it to linear compression to form it into a plug of crimped yarn and heating the plug of crimped yarn.

2. Apparatus for crimping undrawn or partially drawn yarn comprising a first draw roller 'and a second draw roller, means for rotating said first draw roller, means for rotating said second draw roller 'at a peripheral speed greater than that of the first draw roller; a separating roller associated with each of said draw rollers, the axis of rotation of each of the separating rollers being inclined to the axis of the draw roller with which it is associated; a stutter-box crimping chamber; a pair of nip rollers forming feed means to said stutter-box crimping chamber disposed adjacent to said second draw roller, the diameter of said first and second draw rollers being at lea t twice the diameter of said nip. rollers; a setting chamber; heating means for said setting chamber; and conveying means for removing the crimped yarn from the crimping chamber and conveying the crimped yarn through said setting chamber.

3. Apparatus as claimed in claim 2 in which the first and second draw rollers are disposed with their axes of rotation spaced apart by a distance less than twice the sum of their diameters and preferably less than the sum of their diameters.

4. Apparatus for texturizing undrawn or partially drawn yarn comprising a first draw roller and a second draw roller, means for rotating said first draw roller, means for rotating said second draw roller at a peripheral speed greater than that of the first draw roller to thereby draw and develop heat in the yarn, an unheated stutterbox crimping chamber, a pair of nip rollers forming feed means to said stulfer-box crimping chamber disposed adjacent to said second draw roller, heating means disposed adjacent the yarn path between said second draw roller and said pair of nip rollers for subjecting the yarn to heat during its passage between said second draw roller and said pair of nip rollers to maintain said yarn in the heated condition, a setting chamber, heating means for said setting chamber, and conveying means for removing the crimped yarn from the crimping chamber and conveying the crimped yarn through said setting chamber.

References Cited UNITED STATES PATENTS 2,686,339 8/1954 Holt l9-66 2,758,357 8/1956 Goodhue 28-1 3,145,947 8/1964 Stanley 281 3,177,556 4/1965 Van Blerk 2872 3,296,680 1/1967 Iwnick et al 281 LOUIS K. RIMRODT, Primary Examiner.

U.S. C1. X.R. 

